package com.lxmap;

import java.util.HashMap;
import java.util.Map;

public class maptest {
    public static void main(String[] args) {
        Map<String,String> map = new HashMap<>();
        map.put("lx","lib");
        //put提供添加和覆盖两种方法，当添加时返回null，覆盖时，返回被覆盖的元素的value
        System.out.println(map.put("lx","lix"));
        System.out.println(map.put("lixi","lix"));
        int[] arr = {1,2};
        System.out.println(arr.length);
    }
}
